Both of these sponges are a small size when dry and you run the product under water as it doubles up in size and squeeze out all the excess water until it's just damp. You don't want the sponges to be filled with loads of water.
I'm not a huge fan of using this to apply foundation. I find that it sheers out the foundation way too much and just turns it into a tinted moisturizer. Instead, I use this as a final touch to my foundation routine when there are areas that are too dry and have turned flakey.
The Real Techniques Miracle Complexion Sponge is one of the many cheaper alternatives in the market and seems to be the most popular out of all the cheaper ones available.
Unlike the beautyblender, its colour is orange and while it has the egg-like shape, one side of it is completely flat. The flat side is meant to be used for bigger surfaces on the face whereas the smaller tip is for the smaller and hard to get to areas.
Just like the beautyblender, I'm not a fan of using this for applying foundation. I use this to smooth out any areas I feel are still too dry and flakey.
The texture is this is much stranger, but it's not something you notice until you wash it. When washing it, it feels very slimey and it kinds of weirds me out, but it's not a deal breaker in any way.
Which one do I prefer? Really, both sponges do the exact same thing. One is not better than the other except for the price, which Real Techniques wins that round. This works just as well as the beautyblender. When I need to replace a sponge, I see no reason why I would need to spend $20 on a sponge when the $6 one works just as well.